test(lib): cover agent-activity status labels (57→65 tests)

Extract TOOL_STATUS + statusFromPart from stores/events.ts into a pure
status-labels.ts (type-only Part import, erased at runtime; events.ts delegates).
8 tests pin the live 'what is the agent doing' labels: reasoning/text/known-tool
mappings, shared labels (search/edit groups), unknown-tool degrade to
'Running <tool>...', and the no-tool/unknown-type fallthroughs. typecheck clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/status-labels.test.ts

@@ -0,0 +1,49 @@
+import { test } from "node:test"
+import assert from "node:assert/strict"
+import { statusFromPart, TOOL_STATUS } from "./status-labels.ts"
+
+// These labels are shown live while the agent works. A new tool type must degrade
+// to a sensible "Running <tool>..." rather than a blank or wrong status.
+
+const part = (over: Record<string, unknown>) => over as any
+
+test("reasoning parts show Thinking", () => {
+  assert.equal(statusFromPart(part({ type: "reasoning" })), "Thinking...")
+})
+
+test("text parts show Writing", () => {
+  assert.equal(statusFromPart(part({ type: "text" })), "Writing...")
+})
+
+test("known tools map to their friendly label", () => {
+  assert.equal(statusFromPart(part({ type: "tool", tool: "grep" })), "Searching codebase...")
+  assert.equal(statusFromPart(part({ type: "tool", tool: "bash" })), "Running command...")
+  assert.equal(statusFromPart(part({ type: "tool", tool: "edit" })), "Making edits...")
+})
+
+test("read/list/grep/glob and edit/write/apply_patch share labels", () => {
+  for (const t of ["list", "grep", "glob"]) {
+    assert.equal(statusFromPart(part({ type: "tool", tool: t })), "Searching codebase...")
+  }
+  for (const t of ["edit", "write", "apply_patch"]) {
+    assert.equal(statusFromPart(part({ type: "tool", tool: t })), "Making edits...")
+  }
+})
+
+test("an unknown tool degrades to 'Running <tool>...'", () => {
+  assert.equal(statusFromPart(part({ type: "tool", tool: "frobnicate" })), "Running frobnicate...")
+})
+
+test("a tool part with no tool name falls through to the generic label", () => {
+  assert.equal(statusFromPart(part({ type: "tool" })), "Working...")
+})
+
+test("an unrecognized part type falls through to Working", () => {
+  assert.equal(statusFromPart(part({ type: "file" })), "Working...")
+})
+
+test("every TOOL_STATUS entry is reachable via statusFromPart", () => {
+  for (const [tool, label] of Object.entries(TOOL_STATUS)) {
+    assert.equal(statusFromPart(part({ type: "tool", tool })), label)
+  }
+})